1. Field of the Invention
The present invention relates to a power switch apparatus comprising a combination of a breaker part and a disconnect switch part or a disconnect switch part with a lightning arrester therein wherein the parts are independently formed and are in the vicinity of and electrically connected to each other.
2. Description of the Prior Art
A typical power switch apparatus of the prior art is shown in a side elevation view FIG. 1, wherein on a frame 1, first and second supporting insulators 2 and 3 are mounted. The first supporting insulator 2 may be a known lightning arrester, which contains a known lightning arrester element, such as a ZnO element inside the first supporting insulator 2. Hereinafter, the term "first supporting insulator" will refer to either a simple supporting insulator or a lightning arrester containing the lightning arrester element 22 in a supporting insulator.
A fixed contact 4 having a terminal 4a to be connected to a receiving line 11 is mounted on the first supporting insulator 2, and a driving mechanism 6 for driving a moving contact 5 is mounted on the second supporting insulator 3 which holds the driving mechanism in a manner to prevent its horizontal rotation. One end of the moving contact 5 is operatively pivotted by the driving mechanism and the other end of the moving contact 5 is to be connected to and disconnected from the fixed contact 4 by operation of the driving mechanism 6. A driving insulator 7 is mounted on the frame 1 at a predetermined distance from the second supporting insulator 3, in a manner to be rotatingly driven by means of a driving motor (not shown in the drawing) or other suitable mechanism to drive the moving contact 5. The moving end of the moving contact 5 is thereby controllable to either separate from or contact the fixed contact 4, to disconnect or connect a circuit. In other words, the components mounted on the frame 1 constitute a disconnect switch part 100, and the driving mechanism 6 and the driving insulator 7 constitute an operating mechanism of the disconnect switch part 100.
A gas-breaker 10 of an insulator type is mounted on a supporting insulator 9, which is disposed apart from the supporting second insulator 3. A lower terminal 10b of the gas-breaker 10 is connected through a connection wire 12 to the moving contact, and an upper terminal 10a of the gas-breaker 10 is connected to a feeder line 13. A driving motor 14 is provided at the base of the supporting insulator 9 for driving the breaker 10 via a driving rod (not shown in the drawing) in the supporting insulator 9. The components disposed on and under the supporting insulator 9 thus constitute a breaker part 200.
In the power switch apparatus of such prior art, the disconnect switch part 100 and the breaker part 200 are, although electrically interconnected, built in separate groups. It is necessary to provide sufficient room between the disconnect switch part 100 and the breaker part 200, and also around the first supporting insulator 2, the second supporting insulator 3, the driving insulator 7, the frame 7 and the driving motor 14 to enable several workers to work between and around these components; such power switch apparatus are very large and the setting-up requires several workers to work around the components. As gas power switch apparatus comprising a combination of a disconnect switch and breaker in a common gas tank become popular, a demand for reduced size of the set-up area (one advantage of the gas power switch apparatus) becomes the general trend. This is also true for the power switch apparatus comprising a separate disconnect switch part and breaker part. However, as the distance between the disconnect switch part 100 and the breaker part 200 in the conventional power switch apparatus is reduced, the closeness of the disconnect switch part 100 and the breaker part 200 tends to reduce spatial insulation distances between the frame 1 (at ground potential) and the terminal 10b of the high tension as well as between the terminal 10a of the breaker 10 and the driving mechanism 6, which are to assume different potentials upon breaking of the breaker. Accordingly, mere shortening of the distance between the disconnect switch part 100 and the breaker part 200 is not practical; a considerable distance between them is necessary.